17 research outputs found
Programação da produção: Otimização de Layouts Industriais
O problema conhecido na literatura como “Facility layout problem (FLP)”, em que se pretende determinar a disposição de recursos de produção e a sua interação num determinado espaço, é um problema estratégico para a implementação do chão de fábrica de uma empresa pelo impacto que tem na performance da produção.
O problema consiste em encontrar um posicionamento único entre instalações (departamentos, máquinas, células de produção, armazéns, etc.) e localizações no chão de fábrica, de forma a otimizar um ou mais objetivos de produção. O objetivo da criação de layout consiste na otimização do espaço existente, minimização do tempo de produção, redução do custo de manuseamento de matérias, aumento do grau de flexibilidade, entre outros.
A solução do problema deverá especificar a localização relativa de cada departamento (layout em bloco) e numa fase posterior poderá especificar o layout detalhado dentro de cada departamento.
Na presente tese serão apresentados alguns modelos matemáticos para criação de um layout, neste caso vamos usar uma formulação matemática Quadratic Assignment Problem (QAP), uma formulação matemática Mixed Integer Programming (MIP) e uma heurística de Particle Swarm Optimization (PSO) para resolver problemas de layout.
Todas estas formulações e modelos serão postos em prática para a resolução de problemas fictícios.
Numa primeira abordagem iremos resolver problemas fictícios onde abordaremos a formulação QAP para problemas de atribuição de espaço de duas dimensões (x,y) e MIP e em seguida iremos usar a heurística PSO para a resolução de problemas em escala maior e real.The problem known in the literature as "Facility layout problem (FLP)", which is intended to determine the physical layout of industrial facilities, is a strategic problem for the implementation of a company by the impact it has on the production performance.
The problem is to find an unambiguous allocation between facilities (departments, machines, production cells, warehouses, etc.) and locations on the shop floor in order to optimize one or more production goals. The objectives often considered are the optimization of the space, minimizing production time, reduce the handling costs of materials, increased flexibility, among others.
The solution of the problem should specify the relative location of each department (block layout) and at a later stage it can specify the detailed layout within each department.
In this thesis will be presented some methods of resolution in this case we use a discrete Quadratic Assignment formulation (QAP), a Mixed Integer Linear Programming formulation (MIP) and a Particle Swarm Optimization heuristic (PSO) to solve layout problems. All these heuristics will be implemented for solving fictitious problems.
In a first approach we will solve simpler problems where we use the QAP and MIP formulation and following we will use the PSO heuristic to solve problems on a larger scale
Synthesis, characterization, antibacterial and antitumoral activities of mononuclear zinc complexes containing tridentate amine based ligands with N3 or N2O donor groups
The synthesis and characterization of the four zinc(II) complexes [Zn(HL1)Cl-2] (1), [Zn(H2L2)Cl-2](2), [Zn(H2L3)Cl-2] (3) and[Zn(H2L4)Cl-2] (4), where HL1 = (bis-2-pyridylmethyl)amine, H2L2 = (2-hydroxybenzyl- 2-pyridylmethyl) amine, H2L3 = N-2[(pyridine-2-ylmethyl)amino)ethanol, H2L4 = 1-[(pyridine-2-ylmethyl)- amino]-propan-2-ol are reported; (3) and (4) are new while (2) was reported previously but its structure had not been determined. The complexes were characterized by elemental analysis, IR, UV-Vis and NMR spectroscopic, electrospray ionization mass spectrometry (ESI(+)-MS) and tandem mass spectrometry ESI(+)-MS/MS). X-ray diffraction studies were performed for complexes (1)-(3) revealing the presence of mononuclear structures in the solid state. The X-ray analyses of (1) and (3) demonstrate that HL1 and HL2 act as tridentate ligands, while the ligand H2L2 in (2) is bidentate. The cytotoxic properties of the ligands and of all the complexes were examined using human leukemia THP-1, U937 and Molt-4 cells. Complex (4) exhibited the highest cytotoxicity in this series with an IC50 value of 75 +/- 1 mu mol L (1) against U937 cells. Transmission electron microscopy (TEM) reveals ultrastructural changes typical of apoptotic cells. The induction of apoptosis was confirmed by the annexin V assay. The antimicrobial activity of complexes (1)-(4) was also investigated in vitro against four Gram-positive bacteria (ATCC10832, ATCC25923, COL) and the clinical Staphylococcus aureus isolate LSA88 (SEC/SEF/ TSST-1+). Complex (2) showed the most potent inhibitory activity, reaching almost 100% of inhibition against all strains tested. Morphological investigations using TEM indicate that the antibacterial activity of complex (2) may be associated with the inhibition of cell wall and therefore cell division. (C) 2014 Elsevier B. V. All rights reserved
Induction of apoptosis in leukemia cell lines by new copper(II) complexes containing naphthyl groups via interaction with death receptors
The synthesis, physico-chemical characterization and cytotoxicity of four new ligands and their respective copper(II) complexes toward two human leukemia cell lines (THP-1 and U937) are reported (i.e. [(HL1) Cu(mu-Cl)(2)Cu(HL1)]Cl-2 center dot H2O (1), [(H2L2)Cu(mu-Cl)(2)Cu(H2L2)]Cl-2 center dot 5H(2)O (2), [(HL3)Cu(mu-Cl)(2)Cu(HL3)]Cl-2 center dot 4H(2) (3), [(H2L4)Cu(mu-Cl)(2)Cu(H2L4)]Cl-2 center dot 6H(2)O (4)). Ligands HL1 and HL3 contain two pyridines, amine and alcohol moieties with a naphthyl pendant unit yielding a N3O coordination metal environment Ligands H2L2 and H2L4 have pyridine, phenol, amine and alcohol groups with a naphthyl pendant unit providing a N2O2 coordination metal environment These compounds are likely to be dinuclear in the solid state but form mononuclear species in solution. The complexes have an antiproliferative effect against both leukemia cell lines; complex (2) exhibits higher activity than cisplatin against U937 (8.20 vs 16.25 mu mol dm(-3)) and a comparable one against THP-1. These human neoplastic cells are also more susceptible than peripheral blood mononuclear cells (PBMCs) toward the tested compounds. Using C57BL/6 mice an LD50 of 55 mg kg(-1) was determined for complex (2), suggesting that this compound is almost four times less toxic than cisplatin (LD50 = 14.5 mg kg(-1)). The mechanism of cell death promoted by ligand H2L2 and by complexes (2) and (4) was investigated by a range of techniques demonstrating that the apoptosis signal triggered at least by complex (2) starts from an extrinsic pathway involving the activation of caspases 4 and 8. This signal is amplified by mitochondria with the concomitant release of cytochrome c and the activation of caspase 9. (C) 2015 Elsevier Inc. All rights reserved
Data from: Long term impacts of selective logging on two Amazonian tree species with contrasting ecological and reproductive characteristics: inferences from Eco-gene model simulations
The impact of logging and subsequent recovery after logging is predicted to vary depending on specific life history traits of the logged species. The Eco-gene simulation model was used to evaluate the long-term impacts of selective logging over 300 years on two contrasting Brazilian Amazon tree species, Dipteryx odorata and Jacaranda copaia. D. odorata (Leguminosae), a slow growing climax tree, occurs at very low densities, whereas J. copaia (Bignoniaceae) is a fast growing pioneer tree that occurs at high densities. Microsatellite multilocus genotypes of the pre-logging populations were used as data inputs for the Eco-gene model and post-logging genetic data was used to verify the output from the simulations. Overall, under current Brazilian forest management regulations, there were neither short nor long-term impacts on J. copaia. By contrast, D. odorata cannot be sustainably logged under current regulations, a sustainable scenario was achieved by increasing the minimum cutting diameter at breast height from 50 to 100 cm over 30-year logging cycles. Genetic parameters were only slightly affected by selective logging, with reductions in the numbers of alleles and single genotypes. In the short term, the loss of alleles seen in J. copaia simulations was the same as in real data, whereas fewer alleles were lost in D. odorata simulations than in the field. The different impacts and periods of recovery for each species support the idea that ecological and genetic information are essential at species, ecological guild or reproductive group levels to help derive sustainable management scenarios for tropical forests
Lepidotrichilins A and B, New Protolimonoids with Cytotoxic Activity from Trichilia Lepidota (Meliaceae)
Two novel protolimonoids, named lepidotrichilins A (1) and B (2), four known protolimonoids, 21,23-epoxy-7α-21α-dihydroxyapotirucalla-14,24-dien-3-one (3), 21,23-epoxy-7α-21β-dihydroxyapotiru-calla-14,24-dien-3-one (4), dysorone D (5), deoxy-flindissone (6), and the two steroids β-sitosterol (7) and stigmasterol (8) were identified in leaves of Trichilia lepidota subsp. schumanniana (Harms) T.D. Pennington. From wood the coumarin scopoletin (9) was isolated. The structures were established by NMR (1D 1H and 13C-NMR and 2D 1H-1H COSY, HMQC and HMBC), mass spectroscopy and infrared (IR) spectral data. The hexane and methanol extracts of the leaves, the protolimonoids lepidotrichilins A (1) and B (2) (IC50 42.7 µg mL−1) and the protolimonoid deoxy-flindissone (6; IC50 9.3 µgmL−1) exhibited significant cytotoxic activity against the MOLT-4 and U937 leukemic cell lines
Lepidotrichilins A and B, New Protolimonoids with Cytotoxic Activity from Trichilia Lepidota (Meliaceae)
Two novel protolimonoids, named lepidotrichilins A (1) and B (2), four known protolimonoids, 21,23-epoxy-7α-21α-dihydroxyapotirucalla-14,24-dien-3-one (3), 21,23-epoxy-7α-21β-dihydroxyapotiru-calla-14,24-dien-3-one (4), dysorone D (5), deoxy-flindissone (6), and the two steroids β-sitosterol (7) and stigmasterol (8) were identified in leaves of Trichilia lepidota subsp. schumanniana (Harms) T.D. Pennington. From wood the coumarin scopoletin (9) was isolated. The structures were established by NMR (1D 1H and 13C-NMR and 2D 1H-1H COSY, HMQC and HMBC), mass spectroscopy and infrared (IR) spectral data. The hexane and methanol extracts of the leaves, the protolimonoids lepidotrichilins A (1) and B (2) (IC50 42.7 µg mL−1) and the protolimonoid deoxy-flindissone (6; IC50 9.3 µgmL−1) exhibited significant cytotoxic activity against the MOLT-4 and U937 leukemic cell lines